The present invention relates to an electrical switch device comprising:                a casing having a base;        a first and a second conductive track which are fixed to the inner side of the casing and which are electrically insulated from each other;        a first conductive dome which is supported on the base of the casing with a permanent contact being formed with the first track, the first dome being resiliently deformable so as to be able to pass, under the action of an activation pressure along a deformation axis, from a rest configuration, in which it is in electrical contact only with the first track, to a configuration of maximum deformation, in which it forms an electrical contact with the second track so that the first and second tracks are electrically connected; and        an activation device which comprises an operation element which is mounted in the casing so as to slide in an orthogonal manner relative to the axis of deformation, and a movement transformation element which is suitable for applying an activation pressure along the axis of deformation in response to a displacement of the operation element.        
A switch of this type has, for example, been described in the French patent application published under the number 2 803 428 in the name of the same applicant.
A device of this type can allow a change from a first to a second state of commutation by means of a lateral activation movement. The term “lateral” activation is understood to be a pressure, for example, from a user, which is applied in a direction which is substantially orthogonal relative to the plane of the conductive tracks which are to be commutated, or in a direction which is orthogonal relative to the main direction of deformation of the resilient commutation elements. For specific devices, switches with lateral activation are preferable from the point of view of the general size of the device and the ease of operation.
A significant problem in switches with lateral activation of the type mentioned above consists in that they are intended to be able to assume only two states of commutation, corresponding to two position ranges of the activation element along the sliding axis thereof.
There is a requirement for switches with lateral activation having three states of commutation, for example, for use in automatic cameras. In this type of device, the activation of a push-button over a first path brings about automatic updating, and the activation of the push-button over a supplementary path brings about the release.
A significant object of the invention is to provide a switch device with lateral activation having three states of commutation, without significantly increasing the size of the device.